Railway tank car and external support ring therefor

ABSTRACT

There is disclosed an external support ring for a railway tank car including a fluidtight tubular body shell supported by trucks positioned adjacent to the outer ends of the body shell, the external support rings at each end of the car transmitting draft, buff and rotational forces from one of the trucks to the body shell and from the body shell to the other truck. The external support ring has a channel-shaped cross section and is secured to the body shell around the entire periphery thereof forming therewith a boxlike structure, the support ring has a relatively thin cross section above the horizontal midplane of the body shell and a relatively thick cross section below the horizontal midplane, the above structure tends to provide uniform stress distribution in the support ring and to transmit buff, draft and rotational forces from one of the trucks to the body shell and from the shell to the other truck without substantially any underframe; the body shell may be of uniform diameter throughout.

United States Patent [7 21 Inventor Carl E. Becker Sharon, Pa. 21 1 Appl. No. 852,384 [22] Filed Aug. 22, 1969 [45] Patented Dec. 14, 1971 [7 3] Assignee General American Transportation Corporation Chicago, Ill.

[54] RAILWAY TANK CAR AND EXTERNAL SUPPORT RING THEREFOR 12 Claims, 8 Drawing Figs.

[52] US. Cl 105/362 [51] Int. Cl B6lf l/l4, 861d 5/06 [50] Field oiSearch 105/358, 360, 362; 280/5 [56] References Cited UNITED STATES PATENTS 3,277,843 10/1966 Homer et al 105/360 3,336,879 8/1967 l ialcomb. 195L358 3,467,027 9/1969 Brown 3,474,740 l0/l969 Varnes ABSTRACT: There is disclosed an external support ring for a railway tank car including a fluidtight tubular body shell supported by trucks positioned adjacent to the outer ends of the body shell, the external support rings at each end of the car transmitting draft, buff and rotational forces from one of the trucks to the body shell and from the body shell to the other truck. The external support ring has a channel-shaped cross section and is secured to the body shell around the entire periphery thereof forming therewith a boxlike structure, the support ring has a relatively thin cross section above the horizontal midplane of the body shell and a relatively thick cross section below the horizontal midplane, the above structure tends to provide uniform stress distribution in the support ring and to transmit buff, draft and rotational forces from one of the trucks to the body shell and from the shell to the other truck without substantially any underframe; the body shell may be of uniform diameter throughout.

Patented Dec. 14, 1971 4 Sheets-Sheet 1 INVENTOR CARL E. BECKER ATTYS.

Patented Dec. 14, 1971 4 Sheets-Sheet 2 m GNM 4 Sheets-Sheet 3 RAILWAY TANK CAR AND EXTERNAL SUPPORT RING THEREFOR The present invention relates to a support ring for a railway tank car and more specifically to an external support ring completely surrounding and secured to a tubular body shell forming part of the tank car.

It is an object of the present invention to provide a railway tank car comprising a longitudinally extending fluid tight tubular body shell, first and second trucks respectively positioned adjacent to the outer ends of the body shell for supporting the same and each carrying draft connections, first and second external support rings respectively surrounding the body shell adjacent to the outer ends thereof and operatively connected to the first and second trucks respectively, and means securing the support rings to the body shell completely around the periphery thereof to accommodate transmission of forces from the first truck through the first support ring to the shell and through the shell to the second support ring and thus to the second truck.

It is a further object of the present invention to provide a railway tank car of the type set forth in which the support rings have a relatively thick cross section below the horizontal midplane of the body shell and a relatively thin cross section above the horizontal midplane of the body shell to provide generally uniform stress distribution in the support rings around the periphery of the body shell for vertical forces resulting from static and dynamic loading and during impact.

It is another object of the present invention to provide a railway tank car of the type set forth in which the support rings have a channel-shaped cross section to form with the body shell a closed boxlike structure to improve the transmission of I the rotational force resulting from train forces acting on the center plate.

A further object of the present invention is to provide a railway tank car of the type set forth in which each of the support rings includes a stiffening member and two transition structures and a saddle structure, the stiffening member being generally U-shaped with the bight portion on the top of the body shell, the saddle structure being positioned between the adjacent truck and the body shell and extending generally laterally thereof, the transition structures respectively connecting the outer ends of the stiffening member and the saddle structure.

Another object of the present invention is to provide a railway tank car of the type set forth in which first and second elongated support structures are respectively positioned adjacent to the outer ends of the body shell and secured to the underside thereof with the longitudinal dimensions of the support structures extending longitudinally of the body shell for transmission of train action forces from the trucks to the shell.

The invention, both as to its organization and method of operation, together with further objects and advantages thereof, will be best understood by reference to the following specifications taken in connection with the accompanying drawings in which:

FIG. 1 is a side elevational view of a part of a tank car incorporating an external support ring made in accordance with and embodying the principles of the present invention;

FIG. 2 is a plan view of the railway tank car shown in FIG. 1;

FIG. 3 is an enlarged side elevational view of the railway tank car shown in FIG. 1, showing in further detail the external support ring of the present invention;

FIG. 4 is a vertical sectional view of the railway tank car shown in FIG. 3 taken along line 4-4;

FIG. 5 is a bottom view partly in section of the railway tank car shown in FIG. 4 taken along line 5-5;

FIG. 6 is a sectional view of the external support ring shown in FIG. 4 taken along line 6-6;

FIG. 7 is a sectional view of the external support ring shown in FIG. 4 taken along line 7-7; and

FIG. 8 is a schematic diagram showing buff, draft and related rotational forces which result from train action.

There is illustrated and explained in detail hereinafter a railway tank car including a body shell supported at each end by first and second trucks each carrying draft connections and support structure, the body shell having secured therearound adjacent to the outer ends thereof first and second external support rings for transmitting with the support structure bufi, draft and rotational forces from one truck to the body shell then through the body shell to the other truck.

As shown in the drawings, and particularly in FIG. 1 thereof, there is provided a railway tank car including a tubular body shell 101 of uniform diameter closed at either end by a convex head 102 and forming a fluidtight container supported by two eight-wheel trucks 105 positioned respectively at either end adjacent to the convex heads 102, each truck 105 includes a span bolster 107 carrying integral therewith a pair of wings 108 extending transversely of the body shell 101. The trucks 105 and the span bolster 107 provide support for the tank car 100 and also provide for transmission of bufi", draft and rotational forces to and from the body shell 101, all as hereinafter explained. The span bolster 107 carries on the top thereof a wear ring receiver 109, the trucks 105 also including a pivot 110, it being understood that the railway tank car 100 is symmetrical about the centerline as shown in FIG. 1 however, for the sake of simplicity and brevity, only one end of the tank car 100 will be described.

The tank car 100 is also provided on the top thereof with a generally dome-shaped manway leading to the interior of the tank car 100, the top of the tank car 100 also carrying a grating 116 extending generally longitudinally thereof. Placed around the manway 115 and at other convenient places are a plurality of handrails 117, each of the handrails 117 being substantially normal to the grating 1 16, the hand rails being made of piping each in the form of an inverted U." The manway 115, the grating 116 and the handrails 117 provide safe and easy access to the interior of the body shell 101, for instance to clean or to inspect the same.

There is further provided a plurality of ladder structures 118, the ladder structures 118 leading from the grating 116 to the manway 115 and from the grating 116 to a coupling frame structure 120 carrying thereon an overgrating 121 and an upstanding frame 122, the upstanding frame 122 having connected to the top thereof and extending outwardly therefrom a brake wheel 123. The coupling frame structure 120 also carries at the forward end thereof a standard coupler and draft gear 124 forming a draft connection for transmission of draft and buff forces to the tank car structure 100 all as hereinafter described. There is also provided in the tank car 100 a cleanout nozzle 126-at the top of the tank car and drain pipe 127 at the bottom of the tank car, the cleanout nozzle 126 and the drainpipe 127 providing communication between the inside of the tank car 100 and the outside of the tank car 100 thereby to introduce and to drain a cleaning fluid therefrom, the manway l 15 providing entrance for inspection thereof.

As best seen in FIGS. 1, 3 and 5, there is provided a slabbing structure 130, the slabbing structure 130 being crucifonn in shape and having a portion 131 thereof with its greater dimension extending transversely of the body shell 101 and a portion 132 thereof with its greater dimension extending longitudinally of the body shell 101, the slabbing structure 130 being suitably secured to the body shell 101 around the entire periphery of the slabbing structure 130, such as by welding. There is also provided a pair of longitudinally extending generally U-shaped stabilizers 135, the stabilizers having a pair of spaced-apart upstanding sidewalls 136 and a bottom wall 137 interconnecting the sidewalls 136, the sidewalls 136 being suitably secured to the slabbing portion 132 along the entire periphery of the sidewalls 136, such as by welding, the stabilizers being connected at their outer ends to the slabbing portion 132 by a pair of brackets 138 and at their inner ends the stabilizers 135 are connected to a saddle casting 140. The slabbing structure 130 and the stabilizers 135 form with the saddle casting 140, span bolster 107, and the trucks 105 part of the support structure for the body shell 101.

The saddle casting 140 carries on the bottom thereof a wear ring 141 which is received by the wear ring receiver 109, the

saddle casting 140 further including, as best seen in FIG. 3, 4 and 5, a bottom plate 143 generally cruciform in shape and having a pair of arms 144 extending laterally of the body shell 101 and a pair of arms 145 extending longitudinally of the body shell 101, the upper edges of the laterally extending arms 144 carrying upstanding and laterally extending plates 146, the plates 146 being suitably secured to the slabbing 131 and 132, such as by welding. As may be seen, the saddle casting 140 and span bolster 107 provide a connection between the trucks 105 and the body shell 101, and the saddle casting 140 forms a part of an external support ring 150 extending completely around the body shell 101 to support the same and transmit buff, draft and rotational forces from the span bolster 107 thereto.

The external support ring 150, as best seen in FIGS. 3, 4, 6 and 7, includes a generally U-shaped stiffening member 151, the stiflening member 151 being channel-shaped in cross section and having two parallel spaced-apart legs 152 interconnected by a web 153, the legs 152 being suitably secured to the periphery of the body shell 101 wherever the legs 152 come in contact therewith, such as by welds 154, the web 153 being relatively long and the legs 152 being relatively short thereby to reduce the overall transverse dimension of the tank car 100. The stiffening member 151 is generally U-shaped and has an upper arcuate bight portion 155 and a lower straight portion 156, the bight or arcuate portion 155 being positioned on the top of the body shell 101 and the straight portion 156 extending downwardly from the arcuate portion 155 and being spaced from the body shell 101, the legs 152 and web 153 forming with the body shell 101, where the legs 152 are welded thereto, a closed boxlike structure for a purpose to be explained hereinafter.

The external support ring 150 further includes transition plates 160 suitably secured to the stiffening member 151, the slabbing portion 131 and the body shell 101, such as by welds 161, the transition plates 160 having arcuate edges 162 where the plates 160 meet the slabbing portion 131 and the body shell 10]. Two external bottom plates 170 and two curved jacking pads 171 are connected to the downwardly extending straight portion 156 of the stiffening member 151 and the transition plates 160; the bottom plates 170, the plates 146, the jacking pads 171, the transition plates 160 and the stiffening member 151 all being suitably secured to each other, such as by welds 172 and 176, thereby to form with the body shell 101 a completely closed boxlike structure completely around the periphery of the body shell 101, the external support'ring 150 being also operatively connected to the trucks 105 by means of span bolster 107, the boxlike structure resulting in improved transmission and distribution of rotational forces to the body shell 101 by the support ring 150.

There-is also provided a pair of jacking pad gusset plates 175 mounted on the bottom plates 170 and extending upwardly therefrom. There is also provided a pair of side bearings 178 supported by the bolster 107 and connecting the bolster 107 with the bottom plate 143 of the saddle casting 140, the side bearings 178 carrying on the upper surface thereof a pair of ,side bearing gusset plates 179. The jacking pad 171, the side bearings 178 and the side bearing gusset plates 179 all operate in a standard manner and fulfill the usual function.

With reference to FIG. 8, there is diagrammatically shown the rotational forces, M, the buff and draft forces denoted by the horizontal arrows facing to the right as viewed in FIG. 8 and the vertical forces denoted by the arrows facing upwardly as viewed in FIG. 8 produced by the various train action forces. The various forces, as shown, are principally transmitted from the span bolster 107 to the external support ring 150 and thereby into the body shell 101; however, some of the bufi and draft forces are transmitted from the support ring 150 to the trucks 105, these forces generally occurring during dynamic coupler loading. It is apparent from FIG. 8 that the forces created by train action are transmitted to the body shell 101 or the trucks 105 by the present invention, thereby providing for safe operation of the tank car 100.

During operation of the railway tank car 100, various buff, draft and rotational forces are created which must be absorbed or transmitted for continued safe operation of the tank car 100, the external support ring 150 of the present invention providing transmission of the buff, draft and rotational forces from one of the span bolsters 107 to the body shell 101 through the body shell 101 and into the other span bolster 107 through the other support ring 150 all without the necessity of employing underframe. The buff and draft forces are transmitted from the coupler and draft gear 124 through the coupling frame structure to the body shell 101 principally by the slabbing portion 132 and the stabilizers 135. However, the slabbing portion 131 and the stiffening member 151 also transmit some of the draft and buff forces to the body shell 101.

As seen in FIG. 4, the stiffening resistance of the support ring varies with the radial dimension thereof, whereby the upper arcuate or bight portion 155 of the ring 150 has a relatively thin cross section and the bottom of the ring 150 has a relatively thick cross section, the horizontal midplane of the body shell 101 generally providing the dividing line between the thin cross section and the thick cross section of the support ring 150, the greatest stiffening strength of the support ring 150 being on a line at an angle of 45 to the bottom plates and passing through the center of the jacking pads 171 all tend to produce a uniform stress distribution in the ring 150, thereby saving material in the construction of the ring 150 and decreasing the cost thereof.

Relatively high-torsional resistance to the rotational force, M, which results from buff and draft forces, is provided by the external support ring 150 in combination with the body shell 101 which forms at all placed therearound a closed boxlike structure, as seen in FIG. 6 and 7, an important feature being that the external support ring 150 is secured to the body shell 101 completely around the periphery thereof to provide transmission of draft, buff and rotational forces directly between the coupler and draft gear 124, the support ring 150 and the body shell 101 without the need for continuous type underframing. The support ring 150 herein described result in, due to the thin and thick cross section, the closed boxlike structure and the welding to the body shell completely around the periphery thereof, not only the substantial elimination of the usual underframing but also the elimination of any internal support structure which decreases the loading capacity, increases the weight and obstructs the internal cleaning of the tank cars, the external support ring 150 of this invention providing for the first time direct transmission of all forces directly to the body shell 101, whereby the buff, draft and rotational forces are transmitted from one of the coupler and draft gears 124 through the span bolster 107 through one of the support rings 150 to the body shell 101 and through the body shell 101 to the other support ring 150, through the other support ring 150 to the other span bolster 107 and to the other coupler and draft gear 124 and so on, all to provide the required distribution of forces without the usual underframmg.

While there has been provided support structure for a tank car of generally uniform diameter, it is also intended to cover within the scope of this invention support structure for fishbelly tank cars and other tank cars of nonuniform diameter, of single, multiple and special truck configurations, it being understood that there has been described what is at present considered to be the preferred embodiment of the invention, but that various modifications may be made therein, and it is intended to cover in the appended claims all such modification as fall within the true scope and spirit of the invention.

1 claim:

1. A railway tank car comprising a longitudinally extending fluidtight tubular body shell, first and second trucks respectively positioned adjacent to the outer ends of said body shell for supporting the same and each carrying draft connections, first and second span bolsters connecting each of said trucks to said shell, first and second external support rings respectively surrounding said body shell adjacent to the outer ends thereof and located above the longitudinal centers of said trucks and said span bolsters, and operatively connected to said first and second trucks respectively through said span bolsters, and means securing said support rings to said body shell completely around the periphery thereof to accommodate transmission of forces from said first truck through said first span bolster and through said first support ring to said shell and through said shell to said second support ring and thus to said second truck through said second span bolster.

2. The railway tank car set forth in claim 1, wherein said body shell is unifonn in diameter.

3. The railway tank car set forth in claim 1, wherein said external support rings are shaped and arranged to produce a generally uniform stress distribution therein around the periphery of said body shell.

4. The railway tank car set forth in claim 1, wherein said external support rings are welded to said body shell completely around the periphery thereof.

5. A railway tank car comprising a longitudinally extending fluidtight tubular body shell, first and second trucks respectively adjacent to the outer ends of said body shell for supporting the same and carrying draft connections, first and second external support rings respectively surrounding said body shell adjacent to the outer ends thereof and operatively connected to said first and second trucks, respectively, said support rings having a relatively thick cross section below the horizontal midplane of said body shell, said support rings having a relatively thin cross section above the horizontal midplane of said body shell, said relatively thin and relatively thick cross sections being shaped and arranged to provide generally uniform stress distribution in said support rings around the periphery of said body shell for forces developed during movement of said tank car, and means securing said support rings to said body shell completely around the periphery thereof to accommodate transmission of forces from said first truck through said support ring to said shell and through said shell to said second support ring and thus to said second truck.

6. The railway tank car set forth in claim 5, wherein the stiffening resistance of said support rings varies as the radial dimension of said ring varies, said support rings having the greatest resistance to rotational and vertical forces below the horizontal midplane of said body shell along a plane forming an angle of about 45 with the horizontal midplane, said external support rings having the least resistance to rotational and vertical forces along the portion of said support rings on the top of said body shell.

7. A railway tank car-comprising a longitudinally extending fluidtight tubular body shell, first and second trucks respectively positioned adjacent to the outer ends of said body shell for supporting the same and each carrying draft connections, first and second span bolsters connecting each of said trucks to said shell, first and second external support rings respectively surrounding said body shell adjacent to the outer ends thereof and located above the longitudinal centers of said trucks and said span bolsters, and operatively connected to said first and second trucks respectively through said span bolsters, said support rings having a channel-shaped cross section and forming with said body shell a closed boxlike structure to improve the transmission of rotational forces between said support rings and said body shell, and means securing said support rings to said body shell completely around the periphery thereof to accommodate transmission of forces from said first truck through said first span bolster and through said first support ring to said shell and through said shell to said second support ring and thus to said second truck through said second span bolster.

8. The railway tank car set forth in claim 7, wherein said channel-shaped support rings include two parallel spacedapart legs and a web interconnecting said legs, said legs being welded to said body shell completely around the periphery thereof to accommodate transmission of forces from said first truck to said support ring to said shell and through said shell to said second support ring and thus to said second truck.

9. The railway tank car set forth in claim 7, wherein said channel-shaped support rings include two parallel spacedapart legs and a web interconnecting said legs, said web being relatively long and said legs being relatively short, said legs being secured to said body shell completely around the periphery thereof.

10. A railway tank car comprising a longitudinally extending fiuidtight tubular body shell, first and second trucks supporting said body shell and positioned adjacent to the outer ends of said body shell for supporting the same and each carrying draft connections, first and second external support rings respectively surrounding said body shell adjacent to the outer ends thereof and operatively connected to said first and second trucks respectively, each of said support rings includes a stiffening member and two transition structures and a saddle structure, said stiffening member being generally U-shaped with the bight portion positioned on the top of said body shell, said saddle structure being positioned between the adjacent truck and said body shell and extending generally laterally thereof, said transition structures respectively connecting the outer ends of said stiffening member and said saddle structure, and means securing said support rings to said body shell completely around the periphery thereof to accommodate the transmission of forces from said first truck through said first support ring to said shell and through said shell to said second support ring and thus to said second truck.

11. A railway tank car comprising a longitudinally extending fluidtight tubular body shell, first and second trucks respectively positioned adjacent to the outer ends of said body shell for supporting the same and each carrying draft connections, first and second elongated support structures respectively positioned adjacent to the outer ends of said body shell above said trucks and pivotally connected thereto, and secured to the underside of said body shell with the longitudinal dimensions of said support structures extending longitudinally of said body shell for transmission of draft forces from said trucks to said shell, first and second external support rings respectively surrounding said support structures and said body shell adjacent to the outer ends thereof and operatively connected to said first and second trucks respectively at the longitudinal centers thereof, and means securing said support rings to said support structures and to said body shell completely around the periphery thereof to accommodate transmission of forces from said first truck through said first support structure and said first support ring to said shell and from said shell to said second support structure and said second support ring and thus to said second truck.

12. A railway tank c'ar comprising a longitudinally extending fluidtight tubular body shell, first and second trucks respectively positioned adjacent to the outer ends of said body shell for supporting the same and each carrying draft connections, first and second support structures respectively positioned adjacent to the outer ends of said body shell and secured to the underside of said body shell with the longitudinal dimensions of said support structures extending longitudinally of said body shell for transmission of draft forces from said trucks to said shell, first and second external support rings respectively surrounding said support structures and said body shell adjacent to the outer ends thereof and operatively connected to said first and second trucks respectively, each of said support rings includes a stiffening member and two transition structures and a saddle structure, said stiffening member being generally U-shaped with the bight portions thereof positioned on the top of said body shell, said saddle structure being positioned between the adjacent truck and said body shell and extending generally laterally thereof, said transition structures respectively connecting the outer ends of said stiffening member and said saddle structure, said support rings having a relatively thick cross section below the horizontal midplane of said body shell, said support rings having a relatively thin cross section above the horizontal midplane of said body shell, said relatively thin and relatively thick cross sections being shaped and arranged to provide generally uniform tures and to said body shell completely around the periphery thereof to accommodate transmission of forces from said first truck through said first support structure and first support ring to said shell and from said shell to said second support structure and said second support ring and thus to said second truck.

l i I! i 

1. A railway tank car comprising a longitudinally extending fluidtight tubular body shell, first and second trucks respectively positioned adjacent to the outer ends of said body shell for supporting the same and each carrying draft connections, first and second span bolsters connecting each of said trucks to said shell, first and second external support rings respectively surrounding said body shell adjacent to the outer ends thereof and located above the longitudinal centers of said trucks and said span bolsters, and operatively connected to said first and second trucks respectively through said span bolsters, and means securing said support rings to said body shell completely around the periphery thereof to accommodate transmission of forces from said first truck through said first span bolster and through said first support ring to said shell and through said shell to said second support ring and thus to said second truck through said second span bolster.
 2. The railway tank car set forth in claim 1, wherein said body shell is uniform in diameter.
 3. The railway tank car set forth in claim 1, wherein said external support rings are shaped and arranged to produce a generally uniform stress distribution therein around the periphery of said body shell.
 4. The railway tank car set forth in claim 1, wherein said external support rings are welded to said body shell completely around the periphery thereof.
 5. A railway tank car comprising a longitudinally extending fluidtight tubular body shell, first and second trucks respectively adjacent to the outer enDs of said body shell for supporting the same and carrying draft connections, first and second external support rings respectively surrounding said body shell adjacent to the outer ends thereof and operatively connected to said first and second trucks, respectively, said support rings having a relatively thick cross section below the horizontal midplane of said body shell, said support rings having a relatively thin cross section above the horizontal midplane of said body shell, said relatively thin and relatively thick cross sections being shaped and arranged to provide generally uniform stress distribution in said support rings around the periphery of said body shell for forces developed during movement of said tank car, and means securing said support rings to said body shell completely around the periphery thereof to accommodate transmission of forces from said first truck through said support ring to said shell and through said shell to said second support ring and thus to said second truck.
 6. The railway tank car set forth in claim 5, wherein the stiffening resistance of said support rings varies as the radial dimension of said ring varies, said support rings having the greatest resistance to rotational and vertical forces below the horizontal midplane of said body shell along a plane forming an angle of about 45* with the horizontal midplane, said external support rings having the least resistance to rotational and vertical forces along the portion of said support rings on the top of said body shell.
 7. A railway tank car comprising a longitudinally extending fluidtight tubular body shell, first and second trucks respectively positioned adjacent to the outer ends of said body shell for supporting the same and each carrying draft connections, first and second span bolsters connecting each of said trucks to said shell, first and second external support rings respectively surrounding said body shell adjacent to the outer ends thereof and located above the longitudinal centers of said trucks and said span bolsters, and operatively connected to said first and second trucks respectively through said span bolsters, said support rings having a channel-shaped cross section and forming with said body shell a closed boxlike structure to improve the transmission of rotational forces between said support rings and said body shell, and means securing said support rings to said body shell completely around the periphery thereof to accommodate transmission of forces from said first truck through said first span bolster and through said first support ring to said shell and through said shell to said second support ring and thus to said second truck through said second span bolster.
 8. The railway tank car set forth in claim 7, wherein said channel-shaped support rings include two parallel spaced-apart legs and a web interconnecting said legs, said legs being welded to said body shell completely around the periphery thereof to accommodate transmission of forces from said first truck to said support ring to said shell and through said shell to said second support ring and thus to said second truck.
 9. The railway tank car set forth in claim 7, wherein said channel-shaped support rings include two parallel spaced-apart legs and a web interconnecting said legs, said web being relatively long and said legs being relatively short, said legs being secured to said body shell completely around the periphery thereof.
 10. A railway tank car comprising a longitudinally extending fluidtight tubular body shell, first and second trucks supporting said body shell and positioned adjacent to the outer ends of said body shell for supporting the same and each carrying draft connections, first and second external support rings respectively surrounding said body shell adjacent to the outer ends thereof and operatively connected to said first and second trucks respectively, each of said support rings includes a stiffening member and two transition structures and a saddle stRucture, said stiffening member being generally U-shaped with the bight portion positioned on the top of said body shell, said saddle structure being positioned between the adjacent truck and said body shell and extending generally laterally thereof, said transition structures respectively connecting the outer ends of said stiffening member and said saddle structure, and means securing said support rings to said body shell completely around the periphery thereof to accommodate the transmission of forces from said first truck through said first support ring to said shell and through said shell to said second support ring and thus to said second truck.
 11. A railway tank car comprising a longitudinally extending fluidtight tubular body shell, first and second trucks respectively positioned adjacent to the outer ends of said body shell for supporting the same and each carrying draft connections, first and second elongated support structures respectively positioned adjacent to the outer ends of said body shell above said trucks and pivotally connected thereto, and secured to the underside of said body shell with the longitudinal dimensions of said support structures extending longitudinally of said body shell for transmission of draft forces from said trucks to said shell, first and second external support rings respectively surrounding said support structures and said body shell adjacent to the outer ends thereof and operatively connected to said first and second trucks respectively at the longitudinal centers thereof, and means securing said support rings to said support structures and to said body shell completely around the periphery thereof to accommodate transmission of forces from said first truck through said first support structure and said first support ring to said shell and from said shell to said second support structure and said second support ring and thus to said second truck.
 12. A railway tank car comprising a longitudinally extending fluidtight tubular body shell, first and second trucks respectively positioned adjacent to the outer ends of said body shell for supporting the same and each carrying draft connections, first and second support structures respectively positioned adjacent to the outer ends of said body shell and secured to the underside of said body shell with the longitudinal dimensions of said support structures extending longitudinally of said body shell for transmission of draft forces from said trucks to said shell, first and second external support rings respectively surrounding said support structures and said body shell adjacent to the outer ends thereof and operatively connected to said first and second trucks respectively, each of said support rings includes a stiffening member and two transition structures and a saddle structure, said stiffening member being generally U-shaped with the bight portions thereof positioned on the top of said body shell, said saddle structure being positioned between the adjacent truck and said body shell and extending generally laterally thereof, said transition structures respectively connecting the outer ends of said stiffening member and said saddle structure, said support rings having a relatively thick cross section below the horizontal midplane of said body shell, said support rings having a relatively thin cross section above the horizontal midplane of said body shell, said relatively thin and relatively thick cross sections being shaped and arranged to provide generally uniform stress distribution in said support rings around the periphery of said body shell for rotational forces developed during movement of said tank car, said support rings having a channel-shaped cross section and forming with said body shell a closed boxlike structure to improve the transmission of rotational forces between said support rings and said body shell, and means securing said support rings to said support structures and to said body shell completely around the periphery thereof to accommodate transmission of fOrces from said first truck through said first support structure and first support ring to said shell and from said shell to said second support structure and said second support ring and thus to said second truck. 